1. Field of the Invention
The present invention relates to a tissue sampling device, and more importantly, pertains to a single hand operation tissue needle for a biopsy.
2. Description of the Prior Art
Prior art biopsy needles utilize a cannula and a stylet which are both operated using different actuating members. Once the needle was inserted, extreme care has to be taken to insure that the proper actuator member moves in the proper sequence so that the needle member will not access the wrong tissue area, or move inadvertently past or out of the desired biopsy tissue area causing irritation or puncturing of an undesired tissue area. Often the user practitioner, due to unfamiliarity with the needle or procedure, would operate the needle members in an opposite and undesired direction, causing undue stress and trauma in, at or about adjacent tissue areas. Very detailed operational instructions were often hard to follow and required practice on the part of the practitioner, sometimes at the expense of a patient. Another problem was that in having two operating members, two hands were required for proper action of the prior art tissue needles when obtaining a biopsy sample. When additional tissue samples were required, the surgeon attempted, and not always successfully, to insert the biopsy needle into and further within the same puncture hole to obtain another deeper sample. Of course, if alignment with the puncture hole was not obtained, additional tissue damage occurred during the second biopsy procedure.
U.S. Pat. No. 4,667,684 issued to Leigh teaches a pistol grip biopsy device which is designed to be held in one hand by the physician during use. In operation, the Leigh device is substantially complicated, however because of the necessity to manually lock the stylet proximally using the movable hub before the device is advanced into the tissue. Similarly, the hub must be moved again to reextend the stylet to take a sample, and may need to be moved proximally again to permit removal. Even though this movement results in a removable stylet, use of the device probably necessitates control by both hands in many patients.
U.S. Pat. No. 4,733,671 issued to Mehl, the inventor of the present invention, teaches a tissue needle which truly provides one hand operation. Unfortunately, the Mehl device does not have a removable stylet to permit multiple samples to be taken without repositioning the outer cannula.
The present invention overcomes the disadvantages of the prior art by providing a tissue needle requiring single-handed operation at the biopsy point and having a removable stylet.